void main()
{
	float size = 0.1;
	vec2 r = vec2(640,480);
	vec2 p = (gl_FragCoord.xy) / r / size; 

	float color = 0.0;
	
	vec2 t = p*8.; 
	if( mod(t.x, 2.0) > 1. == mod(t.y, 2.0) > 1. )
		color = 0.4; 
	else 
		color = 0.35; 
	
	gl_FragColor = vec4( color*0.5, color,color*0.5, 1.0 );
}
